Nationality: United StatesExecutive summary: Johns Hopkins School of Medicine

Military service: US Army Medical Corps (1917-21, Brig. Gen.)

William H. Welch was a medical researcher who discovered Clostridium perfringens, commonly called the "Welch bacillus", the cause of gas gangrene, and Staphylococcus epidermidis albus, which can cause infection around post-surgical stitches. He was hired as a professor of pathology while Johns Hopkins University was still under construction, and became the First Dean of the School of Medicine, where he left his most lasting mark. Despite his own training as a physician, he had little interest in patient care but endless fascination with research, and his leadership helped establish Johns Hopkins University, Hospital, and Medical School as a leading research institution.

Fearing that his own knowledge of bacteriology was subpar, he sailed to Germany and took a crash course from Robert Koch while Johns Hopkins was still in its planning phase. He enacted the highest admission standards, including the previously un-heard of requirement that medical school students must already be college graduates. When the Hopkins building budget grew strained, he accepted funding from Caroline Harrison and the Women's Fund Committee, in exchange for enacting the groundbreaking policy that women would be admitted on equal footing with men. He hired an old friend, the cocaine-addicted William Stewart Halsted, and resurrected Halsted's career to the point that he became one of his era's most famous surgeons. Later, after the Hopkins complex had been widely heralded as a role model for modern medical institutions, Welch convinced the Rockefeller Institute to contribute underwriting for what he considered the next necessary step, putting the hospital's medical practitioners and teachers on Hopkins' payroll.

His students at Hopkins included Simon Flexner, Walter Reed, and future Nobel laureates George H. Whipple and Peyton Rous. He was the founding editor of the Journal of Experimental Medicine, and with astronomer George Ellery Hale Welch advocated for the founding of what became the National Research Council. He also had a long association with the Rockefeller Institute for Medical Research, serving on various boards and committees as the Institute evolved into Rockefeller University. His father, grandfather, and four of his uncles were all physicians, and his father also served one term as a US Congressman. Welch never married, and spent the last fourteen months of his life at Johns Hopkins as a patient, where he died of cancer in 1934.